I have a new Easymount cold laminator and so far works perfectly with lamination. I have just tried applying a 3x1m print on to 5mm foamboard which normally on my other laminator (same machine just slightly smaller) is perfect, the new machine shows a gap in the centre of the rollers when running the board through, so it has left massive bubbles all the way along the 3m length, I increased the pressure but it didn't help.

Any ideas why it is fine for lamination but not boards? I have a feeling it is the actual foamboard that is the issue because Robert Horne don't send me Forrex Classic anymore and send me some other brand which seems a bit softer, I think maybe it's not as flat as the Forrex brand

Warren,
I have the same problem - same machine or make at least but with Amari foam. I partly resolved the problem with an increase in pressure but it still wasn't perfect. I think it's more to do with the rubber used in the manufacture of the rollers.

Steve, Warren
can't be 100% sure on this but i believe some rollers are designed not to be straight, it is all to do with tracking of the material. Problem is when you put a ridged board in it shows up because it cannot follow the shape. Are you machines specified for mounting to board etc. Also a word of caution increasing the pressure can cause damage & transfer the problem so even laminates won't go through without bubbling so take it easy with the pressure adjustments.

The more expensive foams ie Forex Classic and Foamalux will have a more consistant profile , they tend to be denser , the cheaper foams may have a more variable profile which shows up when laminating, used to be Photolabs would only use Foamalux or Forex Classic although its not like this so much now, could also be the laminate isnt wound tightly throughout the roll and the tension needs to be altered, am no expert by any means but have come across this before.
Never heard of rollers not being straight though?

I have some composite sheet to flood coat next week, I would expect that to be absolutely flat across the 700mm that I need to coat, I guess that exercise will either prove or disprove the flat foam board theory.

That would make sense , if it still happens we can rule out substrate if it doesnt happen let me know and we will help find a solution re substrate. Can you try it over a wider sheet aswell as 700mm is only half the roller.
Say to the branch you have been in touch with me.
thanks

Mine says it can take boards up to 25mm thick, these are 5mm Foamalux 3x1m, when the board is in I can see light shining through the middle area, I have done many dozens of 5mm boards through my old EM1200 and never had a problem.

My reason for thinking it's board is when there is nothing in or just vinyl there is no gap between the rollers, I thought the middle of the rollers were actually thicker than the outsides which is why you are always advised to use the middle and not to one side, if this is true then how cane the outer edges be touching the board but the middle is not

It's a bit frustrating as what would have been a fairly straight forward job has become a pain in my you know where.

I'm with Kevin - our Seal machine has "crowned" rollers, slightly thicker on the middle running back to "normal" on the edges. Just mean when you apply the pressure on the top it sits totally flat.

If they are perfectly flat (like our cheapy chinese one which also cant do foamboard well I'll add - bubbles all down one edge) when you apply pressure it can lift slightly. With this machine we found setting the top roller with scraps of the same thickness board on the far right and left side can help.

Warren
when you try foam board instead of increasing the pressure decrease it instead. If the steel bar in the roller is not thick enough what happens when you put excessive pressure on the ends is the centre will bow. You will have to play with it but may help.

I do not understand why a "crowned" roller would be better that paralell rollers.
the ideal situation is an even pressure along the full length of the rollers, this cannot be achieved if the rollers are not parallel, or so i would assume,
Can a supplier confirm that some laminators have "crowned" rollers, and the reasons?
In practice it would be very costly to machine the rollers with a precise crown, rather than parallel.
Like Kevin says, positive pressure, rather than just the weight of the rollers, can cause problems
I have a jetmounter,(made in china but to decent specs) it has big parallel rollers, and never has a problem with board or vinyl,
Peter

Andy, the reason for the crowned rollers is so to allow for bending of the shaft when pressure is applied, surely the shaft should not bend in the first place?
I know seal are a reputable manufacturer, I just cant get my head around the logic.
If no presssure is applied other than the weight of the rollers, then surely the laminate will not bond properly at the edge of the rollers?
or is a fixed pressure needed for every job?

We use around 30-40psi (depending on the laminate type) on each job. Foamboard and composite get 40psi and I can honestly say they always come out beautifully - except the odd hair but thats not the machines fault!

We have a basic laminator here too (cheapo chinese ebay thing - you've probably seen them, about £500) and as I said previously we could never get foamboard down smooth with this machine even though it has big diameter rollers. It may be the crowned rollers or just the fact the seal machine is better than our cheapo one but something definately makes a big difference in my opinion.

Peter, your not wrong at all. In an ideal world then yes the bar should not bend and the rollers would be perfectly parallel.
Unfortunately it's not practical to make the rollers like that due to the size they would need to be to get zero deflection along the length of the bar when pressure was applied, the longer the roller the thicker it would have to be which is possibly why Warren has never had this problem with his old laminator which is narrower.

out of interest just checked mine and there is .5mm difference between the centre and the edges of a 1370 print all equal lt & rt.
rotating the top roller shows no change so still straight might be .2mm in it.
we set the thickness it should sort out the pressure it works just fine on standard laminating but the only time we tried to laminate a 8x4 board, dam great bubbles every where. no crease just big bubbles as if the fomex was not flat
never tried again but might one day. when i can find a 17ft clear space.

Chris Wool wrote: works just fine on standard laminating but the only time we tried to laminate a 8x4 board, dam great bubbles every where. no crease just big bubbles as if the fomex was not flatnever tried again but might one day. when i can find a 17ft clear space.

Thats the issue we have using our cheapo chinese laminator, as I say this is cured completely by using the Seal machine with crowned rollers

Chris Wool wrote:out of interest just checked mine and there is .5mm difference between the centre and the edges of a 1370 print all equal lt & rt.rotating the top roller shows no change so still straight might be .2mm in it.we set the thickness it should sort out the pressure it works just fine on standard laminating but the only time we tried to laminate a 8x4 board, dam great bubbles every where. no crease just big bubbles as if the fomex was not flatnever tried again but might one day. when i can find a 17ft clear space.

That's exactly it I didn't;t have this problem with my EM1200 which is exactly the same just smaller and an older model

and I had to re-arrange my entire office to run these boards through and then move everything back again, what should have been a 10 min job ended up taking over an hours and lots of frustration

As I said last week, I've just flood coated some composite panels and the material has gone down perfectly. The only difference today is that I put some application tape on the vinyl first whereas I frequently just apply the vinyl on it's own.
My machine sounds like it's much smaller than the others mentioned, it's an 800mm machine, no point in anything bigger with a 760mm printer, however it has suffered the same problem as Warren. I conclude that there are 3 possible causes of the bubbles. That the foamboard is not uniform thickness, the roller is bending and or that the rubber on the roller is not of uniform hardness.